A composition for combating undesired growth of plants, process for the preparation of the compounds, use and process for combating weeds

摘要

The invention relates to 4-methylamino-1,2,4-triazin-5-one of the formula I IMAGE (I) wherein R1 is C3-C8 cycloalkyl or C3-C8 cycloalkyl which is substituted by C1-C4alkyl; C3-C8halocycloalkyl, C3-C8alkyl, C3-C8haloalkyl, 2-furyl, 2-thienyl, phenyl, benzyl, or phenyl or benzyl each substituted by one or more members selected from the group consisting of halogen, C1-C4alkyl, C1-C4haloalkyl, C1-C4alkoxy or C1-C4haloalkoxy, R2 is hydrogen or methyl, and R3 is cyclopropyl, cyclopropylmethyl, C1-C4alkyl, C3-C4alkenyl or C3-C4alkynyl. These compounds have selective herbicidal properties and are therefore pre-eminently suitable for controlling weeds in crops of useful plants, for example in cereals, maize, soybeans and sugar cane. They are also suitable for controlling harmful insects.